Conventionally, it has been known that solubility or absorbability of poorly-soluble drugs is improved by dispersing the poorly-soluble drugs in polymers to form solid dispersions. For instance, there has been known that the solubility and the like are improved by dispersing Griseofulvin in polyethyleneglycol polymer that is a water-soluble polymeric substance to form a solid dispersion (Non-Patent Literature 1).
Incidentally, compounds of the formula (1), which are a subject of the present invention, or pharmaceutically acceptable salts thereof are the compounds which have an α 4 integrin inhibiting activity and are useful as agents for treating inflammatory bowel diseases and the like. Though they can be produced in accordance with the description of Patent Literature 1 and the publication discloses tablets, capsules, and the like wherein the compound of the formula (1) or pharmaceutically acceptable salts thereof are dispensed, there is no disclosure on solid dispersions or solid dispersion pharmaceutical preparations therein. There is no disclosure on solubilized pharmaceutical preparations, either. The compounds of the formula (1) or pharmaceutically acceptable salts thereof are poorly-soluble drugs and their solubility or absorbability needs to be improved.
[Patent Literature 1] WO02/16329
[Non-Patent Literature 1] J. Pharm. Sci., 60, 9, pp 1281-1302, (1971)